In the corrugated cardboard industry, particularly in the making and printing of packing boxes, use is normally made of rotary cutting-out and printing machines consisting of two cylinders operating in the manner of a rolling mill. A rotary cutter, for example, comprises two superposed cylinders turning in opposite directions and at the same circumferential speed. On one of the cylinders, known as the "tool holder", are fastened cutting-out tools consisting of cutting rules generally fitted into sockets formed in a plywood shell matching the shape of the cylinder. The second cylinder, called "cutting counterpart", is given a plastic coating, often of polyurethane. A conventional eccentric bearing adjustment device makes it possible to vary the distance between these two cylinders in order to obtain the necessary cutting pressure whatever the thickness of the cardboard being worked.
The tool holder cylinder and the counterpart cylinder are both rotated by means of gears designed to ensure that the circumferential speed of the tool corresponds to that of the plastic counterpart. These two cylinders are connected to the general kinematics of the processing machine, more particularly to its cyclic sheet feed device, by means of a planetary gear train in which the satellite carrier is rotationally connected to a braking motor-reduction gear unit. The action of this motor-reduction gear unit then enables the user to offset the cutter angularly relative to the general kinematics, so as to bring the tool into phase with the sheet which is to be cut.
In these known arrangements, in which the feed device introduces one sheet after the other at constant intervals theoretically equal to the development of the tool holder, i.e., one sheet for each revolution of the tool holder, the accuracy of the arrival of the sheets in the cutter is generally insufficient for the accuracy required in respect of the position of the cuts in relation to the ends of the sheet.
Some of the sheets of cardboard introduced into the feed magazine of the machine are in fact flat, while others are slightly curved, so that the clearance in the magazine varies from one sheet to another and the sheets may be slightly displaced from the outset. Furthermore, one or more printing machines are generally interposed between the cutter and the feed device, and random slippage may occur on the drive rollers of these interposed machines, thus further reducing the accuracy of transfer of the cardboard sheets. With devices of this kind, the sheets are not presented strictly in phase with the cutting cylinders within the limits of the required precision. It is then generally necessary to make additional front and rear end cuts by means of the rotary cutter, thus necessitating the use of additional blades, and a sheet larger than necessary, resulting in relatively considerable wastage.